Bilabial Substitution Patterns During Consonant Production in a Case Of
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rde iso rs, D De on a ti f a S c t i u McMicken et al., Commun Disord Deaf Stud Hearing Aids 2017, 5:2 n d u i e m s & Journal of Communication Disorders, m o H C DOI: 10.4172/2375-4427.1000175 e f a o r l ISSN: 2375-4427i n a g n r A u i d o s J Deaf Studies & Hearing Aids Research Article Article OMICSOpen International Access Bilabial Substitution Patterns during Consonant Production in a Case of Congenital Aglossia Betty McMicken1, Frederico Salles2, Shelley Von Berg3, Margaret Vento-Wilson4, Kelly Rogers5, Asterios Toutios6 and Shrikanth S Narayanan7 1Department of Communication Sciences and Disorders, Chapman University, USA 2Universidade de Brasília, Brasilia, DF, Brazil 3Department of Communication Sciences and Disorders, California State University, Chico State, USA 4College of Educational Studies, Chapman University, Orange, CA, USA 5Department of Family and Consumer Sciences, Saddleback College, Mission Viejo, CA, USA 6Signal Analysis and Interpretation Laboratory, University of Southern California, CA, USA 7Signal Analysis and Interpretation Laboratory, University of Southern California, CA, USA Abstract Purpose: Congenital aglossia is a rare syndrome in which an individual is born without a tongue. The present paper examines articulatory details of the production of multiple consonants by an aglossic speaker. Method: Real-time magnetic resonance imaging data of the upper airway were collected from the aglossic speaker. Air-tissue boundaries were determined from the video sequences using a segmentation algorithm, and dynamics of vocal-tract constrictions and cross-dimensions were calculated. Results: The aglossic speaker produced the consonants /t, d, th, l ,r, f ,v, s, sh/ with a bilabial closure instead of a normal lingua-alveolar closure; however, in /t/and /d/ the overall vocal-tract configuration presented a cavity anterior to the constriction, which filtered transient and frication sources in a manner similar to normal alveolar production. Conclusion: The aglossic speaker, lacking a tongue apex, has developed a bilabial compensatory strategy to produce multiple consonants with her lips. Keywords: Congenital aglossia; Bilabial substitutions; Acoustics; which investigators report that absence of a tongue, or the presence of a Articulatory maneuvers; Compensatory mechanisms; Speech rudimentary one, may be compensated for by hypertrophy of the floor intelligibility of the mouth. Salles et al. [10] described a case of congenital aglossia in which a female Brazilian speaker elevated the posterior portion of the Introduction floor of the mouth to contact the palate, allowing her to develop speech A person with isolated congenital aglossia (PwCA) is rare. Only and swallowing functions. They suspected the mylohyoid was the 11 cases have been reported internationally [1-11] since it was first primary muscle of movement. However multiple consonant distortions described systematically by De Jussieu in 1718 [12] whose original were reported in this case. McMicken et al. [14,15] reported an overall paper was investigated and described by Salles et al. in 2016 [13]. intelligibility from the 1986 AV tapes of PwCA I of vowels at 78.5% and McMicken and her co-authors [13-20] have reported extensively on initial consonants 77.3%, with considerably variability depending on research from cinefluorographic films and audio-visual (AV) recordings context. collected in 1986 on a 16-year-old female PwCA. This research included perception of vowel production [14], perception of consonant Background production [15], and cinefluorographic examination of articulation The PwCA I was re-examined by McMicken et al. [16-19] and [16], in addition to current re-examination of the PwCA, now in her articulatory movements for speech and swallowing were studied 40s, with electropalatography [17], videoflourography of articulatory using electropalatography (EPG) and videofluorographic films. These movements of pseudo tongue, hyoid and mandible [18], and speech results suggested PwCA I may present with the capacity to capitalize and swallowing kinematics [19]. It should be noted that the PwCA on a variety of actions during eating or swallowing to optimize the was a co-author in previous articles and is currently the subject of this more refined movements of speech. There were highly predictable paper. Because of the attention research on this topic has garnered, correlations of muscles for deglutition and speech, which suggested McMicken and her co-authors have become aware of more individuals that this speaker used the muscular actions developed for deglutition with congenital aglossia, and these individuals present opportunities to enhance speech and resonance. The 2014a [17] EPG study noted for future research. As such, the subject of this article will henceforth be bilateral lip electrode activation in 7 out of 8 trials of /t,d/ productions referred to as PwCA I, and future subjects will continue this cardinality as research on this narrow topic expands. The above investigators are consistent in their comments that *Corresponding author: Margaret Vento-Wilson, College of Educational Studies, Chapman University, Orange, CA, USA, Tel: + 562-243-2334; E-mail: margaret@ the spoken output of congenital aglossic speech was intelligible, but schoolsavers.com demonstrated some vowel and consonant distortions. Such findings would support theories of the speech motor control system as being Received July 11, 2017; Accepted July 25, 2017; Published July 30, 2017 engaged during even the simplest speech tasks, such as babbling or Citation: McMicken B, Salles F, Von Berg SV, Vento-Wilson M, Rogers K, et imitating sounds, and hence would support speech production in which al. (2017) Bilabial Substitution Patterns during Consonant Production in a Case acoustic targets could be achieved with different articulatory strategies of Congenital Aglossia. Commun Disord Deaf Stud Hearing Aids 5: 175. doi: 10.4172/2375-4427.1000175 to realize intelligibility through compensation [20,21]. Rosenthal [9] commented that speech in the congenital aglossic may improve Copyright: © 2017 McMicken B, et al. This is an open-access article distributed considerably when the child learns to use other muscles or structures under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the to substitute for the missing tongue. There have been several cases in original author and source are credited. Commun Disord Deaf Stud Hearing Aids, an open access journal Volume 5 • Issue 2 • 1000175 ISSN:2375-4427 Citation: McMicken B, Salles F, Von Berg SV, Vento-Wilson M, Rogers K, et al. (2017) Bilabial Substitution Patterns during Consonant Production in a Case of Congenital Aglossia. Commun Disord Deaf Stud Hearing Aids 5: 175. doi: 10.4172/2375-4427.1000175 Page 2 of 6 as well as other consonants. The 2015b [19] videofluorographic study lips demonstrated what would be considered as normal mobility. suggested production of the lingua-alveolar stop consonants /t/ and /d/ She reported never receiving oral medical, surgical, or therapeutic may be possible through a substitution pattern of lower incisors, lower intervention, and additionally reported that all speech and feeding lip, and mylohyoid to constrict the anterior oral cavity for intelligible milestones were met without assistance other than the use of a bottle production. with a longer stem and wider nipple during infancy. The following link demonstrates the intelligibility of the subject while reading the In 2015, and again in 2016, a collection of real time MRIs (rtMRI) “Rainbow Passage:” were acquired on PwCA I. These rtMRIs allowed for an in-depth analysis and a greater understanding of the importance of a pattern https://youtu.be/UOtWR1U9vMwhttps://youtu.be/ of bilabial constriction in consonant production for PwCA I. Since it UOtWR1U9vMw was obvious from the rtMRIs that bilabial constriction was utilized for multiple consonants, the question arises: what are physiological Stimuli, data acquisition and analysis differences between the consonant productions that allowed for Speech stimuli consisted of multiple phoneme combinations, intelligible perception? words, phrases, and sentences read by PwCA I. Speech responses were acquired using an rtMRI protocol developed specifically for Research Questions the dynamic study of upper airway movements [22,23]. Experiments 1.Is there an explanation that would account for intelligible were performed on a GE Signa Excite 1.5T scanner with a custom perception due to similar physiological production of /p,b/ and eight-channel upper airway receiver coil. The airway of was imaged /t,d/? in the midsagittal plane using a multishot short spiral readout spoiled gradient echo pulse sequence (flip angle: 15 degrees; slice thickness: 6 2.What is the degree of constriction and duration characteristics of mm; readout time: 2.5 ms, repetition time: 6.004 ms). The rtMRI data multiple consonant productions? were reconstructed from two anterior coil elements, which had the Methods most sensitivity to the upper-airway. Video sequences were formed at a frame rate of 83 fps (spatial resolution was 2.4 mm/pixel) using Subject a view-sharing reconstruction scheme. Audio was simultaneously recorded at a sampling frequency of 20 kHz inside the MRI scanner PwCA I is a 46-year-old woman born without a tongue. PwCA I while the subject was imaged, using a custom fiber-optic microphone presented with micrognathia (severe Class II malocclusion)